package com.mux.util.coder;

import java.security.MessageDigest;

import javax.crypto.KeyGenerator;  
import javax.crypto.Mac;  
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import sun.misc.BASE64Decoder;  
import sun.misc.BASE64Encoder;  

/**
 * 
 * @author devin.chen
 *
 */
public abstract class Coder {
	 public static final String KEY_SHA = "SHA";  
	    public static final String KEY_MD5 = "MD5";  
	  
	    /** 
	     * MAC算法可选以下多种算法 
	     *  
	     * <pre> 
	     * HmacMD5  
	     * HmacSHA1  
	     * HmacSHA256  
	     * HmacSHA384  
	     * HmacSHA512 
	     * </pre> 
	     */  
	    public static final String KEY_MAC = "HmacMD5";  
	  
	    /** 
	     * BASE64解密 
	     *  
	     * @param key 
	     * @return 
	     * @throws Exception 
	     */  
	    public static byte[] decryptBASE64(String key) throws Exception {  
	        return (new BASE64Decoder()).decodeBuffer(key);  
	    }  
	  
	    /** 
	     * BASE64加密 
	     *  
	     * @param key 
	     * @return 
	     * @throws Exception 
	     */  
	    public static String encryptBASE64(byte[] key) throws Exception {  
	        return (new BASE64Encoder()).encodeBuffer(key);  
	    }  
	  
	    /** 
	     * MD5加密 
	     *  
	     * @param data 
	     * @return 
	     * @throws Exception 
	     */  
	    public static byte[] encryptMD5(byte[] data) throws Exception {  
	  
	        MessageDigest md5 = MessageDigest.getInstance(KEY_MD5);  
	        md5.update(data);  
	  
	        return md5.digest();  
	  
	    }  
	  
	    /** 
	     * SHA加密 
	     *  
	     * @param data 
	     * @return 
	     * @throws Exception 
	     */  
	    public static byte[] encryptSHA(byte[] data) throws Exception {  
	  
	        MessageDigest sha = MessageDigest.getInstance(KEY_SHA);  
	        sha.update(data);  
	  
	        return sha.digest();  
	  
	    }  
	  
	    /** 
	     * 初始化HMAC密钥 
	     *  
	     * @return 
	     * @throws Exception 
	     */  
	    public static String initMacKey() throws Exception {  
	        KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_MAC);  
	  
	        SecretKey secretKey = keyGenerator.generateKey();  
	        return encryptBASE64(secretKey.getEncoded());  
	    }  
	  
	    /** 
	     * HMAC加密 
	     *  
	     * @param data 
	     * @param key 
	     * @return 
	     * @throws Exception 
	     */  
	    public static byte[] encryptHMAC(byte[] data, String key) throws Exception {  
	  
	        SecretKey secretKey = new SecretKeySpec(decryptBASE64(key), KEY_MAC);  
	        Mac mac = Mac.getInstance(secretKey.getAlgorithm());  
	        mac.init(secretKey);  
	  
	        return mac.doFinal(data);  
	  
	    }  
}  

